This invention relates to an analyzing apparatus for analyzing a surface of an object by charged particles, such as the Auger electrons known in the art. More particularly, this invention is applicable to an analyzing apparatus comprising a cylindrical mirror type analyzer for analyzing energy of the charged particles which are emitted from the surface.
As will later be described with reference to a few of fourteen figures of the accompanying drawing, a conventional analyzing apparatus of the type described comprises a radiant beam radiator which has a radiant beam radiator axis and which radiates a radiant beam, such as an electron beam, onto the surface of the object to make the surface emit the charged particles.
The cylindrical mirror type analyzer comprises outer and inner coaxial cylindrical electrode members having a common cylinder axis which is coincident with the principal axis. The outer and the inner cylindrical electrode members define an outer and an inner room, respectively. A space is defined between the outer and the inner cylindrical electrode members. The inner cylindrical electrode member has an inlet and an outlet opening each of which surrounds the principal axis.
The cylindrical mirror type analyzer acts to analyze the charged particles which enter the space through the inlet opening and come out thereof through the outlet opening.
In one of such conventional analyzing apparatus, the radiant beam radiator and the cylindrical mirror type analyzer are individually attached to an inner surface of a vacuum vessel with the radiant beam radiator disposed outwardly of the outer cylindrical electrode member. With this structure, the radiant beam radiator can not be disposed nearer to the surface of the object than the outer cylindrical electrode member. Therefore, the radiant beam has a wide diameter on the surface. As a result, it is impossible to obtain a high resolution of analysis. In addition, the analyzer and the radiant beam radiator should individually and precisely be assembled in the vacuum vessel. Such a precise assembly is laborious and difficult. On the other hand, they must be disassembled from each other on maintenance or sweep of the analyzing apparatus. The above-mentioned structure makes such a disassembly cumbersome and difficult on maintenance or sweep of the apparatus.
An etching beam radiator is often housed in the vacuum vessel to radiate an etching beam, such as an ion beam, onto the surface of the object and to thereby etch the surface. The surface of the object is etched by the etching beam in a direction of a depth of the object. The etching beam radiator is necessary in carrying out the elementary analysis along the direction of the depth. The etching beam radiator gives rise to a like problem.
Another of the conventional analyzing apparatus is disclosed in U.S. Pat. No. 4,048,498 issued to Robert L. Gerlach et al. In the analyzing apparatus according to Gerlach et al, the radiant beam radiator is disposed in the inner room with the radiant beam radiator axis rendered coincident with the principal axis. With this structure, it is possible to obtain a high resolution because the radiant beam radiator can be disposed adjacently of the surface of the object. However, it is necessary to miniaturize the radiant beam radiator so as to be placed in the inner room. Thus, the high resolution is achieved at the cost of simpleness of the structure.
Still another of the conventional analyzing apparatus is revealed in U.S. Pat. No. 4,205,226 issued singly to Robert L. Gerlach. In the Gerlach analyzing apparatus, the radiant beam radiator is disposed along the principal axis from outside of the inner room into inner room. The radiant beam radiator axis is coincident with the principal axis.
With the Gerlach analyzing apparatus, it is also possible to obtain a high resolution because the radiant beam can be disposed adjacently on the surface of the object.
However, the radiant beam is incident onto a surface of an object along the radiant beam radiator axis. The incidence of the radiant beam onto the surface gives rise to emission of charged particles from the surface. The charged particles are finally collected on a sensor arranged along the radiant beam radiator axis. Inasmuch as the radiant beam and the sensor are coaxial, the sensor should be provided with an aperture through which the radiant beam passes. Precise working of the sensor is necessary to form the aperture. Thus, the high resolution is achieved at the cost of simpleness of the structure.
In either of the analyzing apparatus according to Gerlach et al and to Gerlach alone, the etcing beam radiator is placed at the outside of the analyzer. Therefore, a large angle is formed between the etching beam radiator and the radiant beam radiator. As a a result, a resolution of analysis is low in the direction of the depth of the object. At any rate, each analyzing apparatus is disadvantageous in that assembly and disassembly are difficult on manufacturing and maintaining the apparatus, respectively, like the aforementioned conventional apparatus.